Debris conveyor chutes made of a plurality of detachable chute sections are known; see for example U.S. Pat. No. 3,627,090 the entire contents of which are incorporated herein by reference; see also U.K design no. 1,025,054. Such chutes are usually erected outside of and adjacent the wall of a building so as to provide a mechanism whereby waste materials may be easily and safely disposed of by being directly conveyed to a disposal bin at the base of the building.
However, as the height the conveyor chute is required to reach increases so does the number of chute sections which are necessary in order to construct the debris chute. This may pose a significant storage and transportation problem if the chute sections are integral built units. Such units a bulky and thus require a relatively larger volume of storage area and may necessitate frequent trips between the storage site and the work site in order to accumulate enough chute sections to make a debris conveyor of the desired height.
This storage and transportation problem may be meet if each of the chute sections may be broken down into a sheet member from which the tubular chute may be reconstructed. Such rebuildable chute sections may be built by rolling up opposed edges of the sheet to give the desired tubular form and using ordinary nut and bolt fasteners to join the opposed edges together; the reverse being done in order to recover the (flat) sheet to facilitate storage and transport, i.e. minimise the space occupied by the material making up the chute. However, a problem to be faced is how to maintain in place either the nut or bolt while engaging or disengaging the fastener form the sheet; usually this means that a person must be placed on the inside of the tubular section who will then cooperate with a person on the outside so as to remove the nuts and bolts, i.e. the person inside may merely hold on to a nut (using a wrench, etc.) while the person outside turns the bolt. This is a cumbersome procedure and may be expensive in it requires two persons to do the work. Another problem with ordinary nut and bolt fasteners relates to the vibration energy to which the chute sections are exposed during use. If ordinary nuts and bolts are used they will have a tendency to loosen with time and even fall out; if enough bolts and nuts fall out the overall structural integrity of the chute can be compromised. Lock washers may be used but they have a tendency to wear due to the repeated taking apart and rebuilding of the chute sections.
Accordingly, it would be advantegeous to have a tubular section (suitable for chutes) which may be made from a sheet and be readily built and broken down.
It would, in particular, be advantageous to have a debris conveyor chute system which is built from sheets which are relatively easy to connect and disconnect along opposed edges thereof.
It would also be advantageous to be able to have a tubular section whereby the screw interlock means may be effectively restrained from screw disengagement due to vibration, or otherwise.